4 Extraction of teeth
Not all extractions are straightforward; sometimes teeth fracture or there is risk of damage to adjacent structures during the process. It is important to attempt to evaluate, before the extraction, the likely degree of difficulty and the chances of adverse events. This maximizes the chance of things going according to plan.
A patient may give a history of previous difficult extractions, anxiety or wound healing problems. They may describe medical factors interfering with their fitness to undergo the procedure under local or general anaesthesia, such as severe ischaemic heart disease. Valvular heart disease and anticoagulation therapy require special precautions. Some medical factors indicate risks of local problems (e.g. leukaemia and risk of infection, or osteogenesis imperfecta and risk of fracture).
Look for signs of limited access, as occurs with severe temporomandibular joint disease, burn scars around the lips or a restricted view due to abnormal tooth position or crowding. Teeth so displaced from the arch that forceps cannot be applied in the conventional way may be more difficult to remove. Incompletely erupted teeth require a transalveolar approach.
A bulky alveolus and severe attrition (particularly of posterior teeth) are associated with difficult extractions. Cervical abrasion cavities, extensive restoration and clinically evident fractures all predispose to fracture during extraction. Extensive caries, especially at the site of application of the forceps beaks, also makes fracture more likely.
Radiographs may show extensive caries, large restorations, root-filled teeth (all of which may make fracture more likely) and also demonstrate bulbosity, curvature and other abnormalities of the root not visible clinically. The loss of bone due to periodontal disease, or increased density, influences ease of extraction. Also, if the tooth is likely to be in close relation to the inferior alveolar nerve or maxillary antrum it is important to assess that relation in advance.
The consent of the patient must be obtained before any procedure, and it is usual to record this consent in writing. It is not possible for a patient to consent to a procedure unless they know what is being proposed and its likely implications. For this reason careful assessment, as outlined earlier, is essential. A clear diagnosis must be made.
The design of forceps has remained remarkably constant over many years: it is difficult to improve on the basic shapes. All forceps consist of two blades and handles joined at a hinge. The inner aspects of the blades are concave to fit the root accurately; they should not touch the crown of the tooth. The blades have sharp edges to cut periodontal ligament fibres and are wedge-shaped to dilate the socket. The blades are applied to the buccal and lingual aspects of the root. There are many designs, but for the purpose of this book we will restrict discussion to those most commonly used.
Forceps for extracting upper anterior teeth are of a simple design (Fig. 4.1). The handles are straight and 12–14 cm long, joined at a hinge to the beaks, which are 2–3 cm long. The handles are contoured on their outer surface to allow a good grip. The beaks are both concave on their inner aspect (Fig. 4.2), shaped to fit around the root of the tooth as closely as possible (Fig. 4.3) when the forceps are applied in the long axis of the tooth. The beaks are applied labially and palatally. All extraction forceps can be seen as modifications of this basic design.
Fig. 4.3 Fit of the beaks of upper straights around a tooth root. If the blades fit closely around the root, the load will be evenly distributed (left). If there is a poor fit, the load will be concentrated at the points of contact (right).
These forceps can be applied to the long axis of anterior teeth, gaining access by the patient opening their mouth fairly widely (Fig. 4.4). However, if one were to attempt to use these forceps on an upper first premolar, there is a risk of traumatizing the lower lip. Forceps for use in the upper jaw further back than the canine have a curve in the beak (Fig. 4.5), which keeps them above the lip when they are in the long axis of the tooth. The beaks of these forceps are also concave on their inner aspect to fit the root of upper premolars.
These forceps could be used to extract posterior teeth, but for teeth with multiple roots, forceps are available with beaks specifically designed to fit complex root forms (Fig. 4.6). In principle, the more closely the beaks are adapted to the roots, the more widely the forces of extraction are distributed and the lower the likelihood of tooth fracture. The buccal beak has a point to fit into the bifurcation, with concavities on either side to fit around the buccal roots and a broader concave palatal beak. Because of this distinction between buccal and palatal beaks, there must be separate designs for left and right sides of the mouth.
For all upper extractions it is necessary to push firmly in the long axis of the tooth during extraction (see p. 32). For this reason many forceps for upper posterior teeth have a curve at the end of the handle (‘Read pattern’) so that they fit in the palm of the hand (Fig. 4.7). This inevitably means that such forceps must have separate designs for right- and left-handed operators (Fig. 4.8).
Access for extraction of teeth far back in the mouth can be difficult. A further variation involves a step in the beaks of the forceps (Fig. 4.9), which enables you to put the beaks on the upper third molar whilst avoiding the lower lip.
If you were to attempt to apply upper anterior forceps to a lower anterior tooth you would have difficulty in getting past the nose and upper alveolus. In the UK it is usual to overcome the problem by using forceps with a right-angled bend in them; this permits the handles to come straight out of the mouth when the beaks are in the long axis of the tooth (Fig. 4.10). The beaks of these simple forceps are similar to those used on upper anteriors. Such forceps can be used effectively on all lower teeth, from second premolar to second premolar.
Just as with the forceps for upper teeth, beak design has been modified for multiple-rooted teeth. Full molar forceps have a point and two adjacent concave facets on both buccal and lingual beaks (Fig. 4.11).
The upper and lower premolar-style forceps are available with narrower beaks for teeth with very small roots, such as lower incisors, or for single retained roots of multi-rooted teeth. They are designated with the suffix ‘N’ (for narrow) on their catalogue number. The narrow variant of the upper straight forceps is designated ‘S’ (for small), but there is a broad, short variant for canines also denoted ‘S’.
Forceps designed to actively lift multi-rooted teeth out of their sockets by forcing pointed blades beneath the bifurcation (‘cowhorns’) do not allow the tooth to be firmly grasped and carry a small risk of fracturing the jaw by forcing roots apart if the tooth does not move. Similar forceps have been designed with beaks to cut or fracture a molar tooth (‘eagle beaks’). The potential risk associated with the use of these instruments makes them unsuitable for beginners: they should be used, only with great care, by the experienced operator.
During all extractions it is necessary to push the forceps firmly towards the apex of the tooth. For maxillary teeth this is achieved by pushing on the end of the handle. In order to maintain that position, the end of the handle must rest centrally in the palm of the hand, with the wrist held straight (Fig. 4.12). The first three fingers are placed around the handles and initially the little finger is placed between the handles to help hold them apart. The little finger can be brought around the handle once the forceps are thoroughly applied. The thumb is braced on the handle but not placed around it—that could produce too great a compressive force and tends to misalign the instrument in the hand. The thumb should not be placed between the handles as this also misaligns the instrument and tooth breakage during extraction risks injury to the thumb.
For mandibular extraction the position of the forceps is very similar (Fig. 4.13), but it is not necessary to push in the long axis of the forceps, so rigid adherence to keeping the end of the handle in the palm is less important. Nevertheless, the further the hand is from the hinge and beaks, the greater will be the leverage applied, and the lower the amount of interference of the hand with the patient’s face.
The positioning outlined below is intended for extraction in a patient who is sitting up or partly supine and for an operator who is standing. It is perfectly possible to extract teeth low-seated, in the fully supine patient, but novices should start as shown here and modify the techniques for low-seated work later if they desire. The description assumes a right-handed operator, but a mirror image of the technique can be employed by left-handers.
The positioning is determined by the need to push in the long axis of the tooth. The operator stands in front and to the right of the patient (Fig. 4.14). The operator’s legs should be spaced so that it is possible to push hard with the right leg which should be to the rear and straight. The left leg should be forward and slightly bent. Both feet should be close to the chair and pointed towards the patient’s head. The back should be kept straight. The patient should be tipped back by about 30° so that the surgeon can see directly into the mouth. The height of the chair should be adjusted so that the tooth to be extracted is about at the height of the operator’s elbow. The patient’s head is tipped just far enough to their right that access to the tooth is comfortable.
For teeth in the lower left quadrant, the operator stands much as for maxillary extractions (Fig. 4.15), but the patient can be placed a few inches lower. When the operator’s back is straight and the forceps are applied to the tooth, both of the operator’s wrists should be in a comfortable neutral position. This will be helped if the patient turns slightly toward the operator.
For teeth in the lower right quadrant the operator stands behind the patient (Fig. 4.16) but beside the head, usually on the patient’s right (occasionally, depending on the angulation of the tooth, it is more comfortable to stand on the other side). The chair can be tipped further back than for the maxillary teeth (maybe as much as 45°) and its height can be a little lower than when standing in front for the left side. There is little advantage in spreading the legs widely; for this extraction one is pushing down.
The left hand is used to support the jaw and stabilize it during extraction. It also holds soft tissue out of the way to permit good vision. For maxillary teeth, the index finger and thumb are placed either side of the alveolus adjacent to the tooth to be extracted (Fig. 4.17). This usually requires the elbow to be up in the air. The remaining fingers are either kept straight or bunched tightly, so that they do not rest hard against the face or eyes.
For extractions in the mandible two fingers and the thumb are used (Fig. 4.18). For the lower left this means placing the index and second fingers either side of the alveolus in the mouth and the thumb beneath the mandible outside the mouth to lift up. For the lower right use the index finger and thumb inside the mouth and the second finger beneath the jaw, supporting it.
An extraction can be described as comprising two movements: the forceps are applied along the root of the tooth with apical pressure, then the blades are closed while maintaining the apical pressure; the second movement loosens or displaces the tooth.